The purpose of this project is to define the morphologic basis of intestinal motor disorders and to correlate abnormalities of structure with abnormalities of function and the clinical behavior of each disorder. We plan to continue our studies of the smooth muscle and myenteric plexus of the gut in chronic idiopathic intestinal pseudo-obstruction, diabetic gastroparesis, diabetic diarrhea, idiopathic megacolon, cathartic colon, severe idiopathic constipation, esophageal motor disorders, and the extraintestinal nervous system in diabetic gastroenteropathy. We also plan to define the normal structure of the myenteric plexus and smooth muscles of premature infants, infants, and young children and to compare this with the findings in infants and young children who suffer from a variety of forms of intestinal pseudo-obstruction. Tissue made available via surgery or autopsy will be systematically studied by conventional light microscopy, silver staining of longitudinal sections of the myenteric plexus, and electron microscopy. Electron microscopy will especially be used to define differences between the various neural and muscle diseases encountered and to compare them with normals. In many cases, patients will have been clinically evaluated by the investigators and we will be able to correlate the radiographic and/or esophageal manometric findings with the pathologic findings. In other cases, tissue will be sent from outside institutions accompanied by appropriate records, x-rays, and the results of esophageal and gastroduodenal manometries. Our aims are: 1) to define the nature and distribution of morphologic abnormalities (if present) in order to achieve a better understanding of pathogenesis; 2) establish diagnostic criteria by which pathologists will be able to diagnose some of these disorders; 3) correlate abnormalities of function with abnormalities of structure in order to increase diagnostic accuracy.